did tail semantics change?

[Alan Cox]

> So, bug or no bug? And is it just funny on F7 or can you repro it elsewhere


The current documentation says:

|    On older systems, the leading `-' can be replaced by `+' in the
| obsolete option syntax with the same meaning as in counts, and obsolete
| usage overrides normal usage when the two conflict.  This obsolete
| behavior can be enabled or disabled with the `_POSIX2_VERSION'
| environment variable (*note Standards conformance::), but portable
| scripts should avoid commands whose behavior depends on this variable.

so basically it was disabled as it violated the required standards
compliant behaviour